Encouraging results from a prototype micropitting test usingspecially designed gears (20:30 tooth ratio, tip relief, and a 560mm radius pinion crown) on the standard FZG test rig were reportedat the 1998 AGMA Fall Technical Meeting. Subsequently, the authors’company purchased several sets of these experimental AGMA testgears and attempted to develop a new test procedure to evaluatemicropitting as an alternative to FVA Procedure 54. The newrelatively short test procedure involves running the test gears onthe standard FZGtest rigwith oil circulation for 168 hours at loadstage 10 and 1500 rpm. The 5–gallon reservoir of test oil is keptat 60 C throughout the test. The oil is cleaned by an in–linefilter (200 =6 m) before it is injected into the gear mesh at 2liters/minute. At the end of test, the gears are rated formicropitting, weight loss, pitting, and scuffing. The most commondamage mode was micropitting, with only occasional occurrences ofpitting and no occurrences of scuffing. Other modes of failure suchas gear tooth bending did not occur at these conditions. Theinvolute profile deviation of the gear teeth was not measured.
Five commercially available ISO VG 320 gear oils, withperformance in the FVA Procedure 54micropitting test ranging fromFLS 9–low to FLS >10–High, were evaluated using thisprocedure. The degree of micropitting coverage ranged from 34% to7% in the new test procedure. Micropitting generally originated inthe middle of the gear tooth, instead of the root or tip. Overall,there was excellent correlation of the degree of micropittingdamage between the new test procedure and FVA Procedure 54.
- Edition:
- 04
- Published:
- 10/01/2004
- Number of Pages:
- 8
- File Size:
- 1 file , 260 KB
Reviews
There are no reviews yet.